I would argue that you would want to get rid of all the organisms
but one, man. We have starting examples of this in the barrier
facilities in which many rodents are maintained. We can readily
synthesize the vitamins provided by our current bacteria, so why
not eliminate the parasites entirely? It certainly would lower
our energy requirements.

You have to deal with time scale differences. Over the long
term our existing ecosphere is probably unstable. What we
now see is due to long term downstream effects of earlier
biosphere changes. Those changes continue even today, just
slowly enough that we don't realize many of them.

I doubt *any* complex system can be constructed that is not
unstable or very chaotic. Only if you have relatively simple
systems can you have some hope of predicting and following
all of the interactions.

If you are trying to recreate a biosphere with pre-existing tools
(microorganisms and higher plants & animals), then you probably
have to go for complexity (because nature has evolved to be
that way). If you are willing to apply energy & chemical fixes
and you aren't losing any "mass", then the system is by definition
self contanined and you can drive the imbalances in any direction
you want.

> I wrote: > > With regard to the stale atmosphere issues, these are taken care of by> > molecular sorting. With regard to food production, people seem to be> > still thinking ancient-tech. A full complement of nutritious & tasty> > gruels with all the necessary vitamins, proteins, fats & carbohydates> > will be able to be produced in bacteria/yeast, directly from sunlight> > or electricity, using biotech, long before we have hard nanotech> > available.> > I see zero economic pressure for the development of such technology.> Who will fund the research and why would they bother to fund it?

Why? So we are hard-wired to think dead babies are bad.
If your life (or the survival of the species) depended on a
rapid turnover of dead babies to develop workable neo-genomes,
then I suspect you would be willing to adapt.

[Please note when the news reporters or others read this note
in the Extropian archives -- I am *not* suggesting this is a
reasonable strategy in any situation other than the "last
resort" scenario.]